1. Field of the Invention
The present invention relates to a pixel compensation method for an image sensor, more particularly to a method for performing compensation of response intensities of pixels in a pattern obtained by an image sensor.
2. Description of the Related Art
An image-capturing device, such as a digital camera, includes an image sensor. The image sensor is typically a complementary metal oxide semiconductor (CMOS) sensor or a charge coupled device (CCD) sensor. The image sensor converts light into electrons at photosites. By placing a color filter array, such as a Bayer filter, over the sensor, a mosaic pattern of red, green, and blue pixels of different intensities is obtained. A demosaicing algorithm is then used to convert the mosaic of separate colors into an equally sized mosaic of true colors. As an example, the true color of a single pixel can be determined by averaging the values from the closest surrounding pixels by using interpolation techniques.
However, prior to performing demosaicing, the response intensities of the pixels may be uneven at areas where there should be uniformity due to such factors as lighting, circuit design characteristics, color differences, and defects in a lens of the image-capturing device. Such an adverse affect to the response intensities of the pixels is particularly marked among pixels of different columns and rows of the obtained pattern. Differences in pixel response intensities may cause color spots of localized color unevenness.